Commutating field coil insulation and support structure



NOV. 24, 1970 c, THARP 3,543,067

COMMUTATING FIELD COIL INSULATION AND SUPPORT STRUCTURE Filed March 2-5, 1968 WITNESSES: INVENTOR fin Charles M. Tharp ATTOR EY United States Patent O 3,543,067 COMMUTATING FIELD COIL INSULATION AND SUPPORT STRUCTURE Charles M. Tharp, Westminster, Califi, assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Mar. 25, 1968, Ser. No. 715,618 Int. Cl. H02k 19/26 US. Cl. 310-194 6 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION The present invention relates generally to dynamoelectric machines, and particularly to an insulating support structure for commutating field coils employed in said machines.

Present insulating structures for edge wound strap coils employed on commutating pole pieces comprise generally a four piece molded insulating shield disposed between the pole piece and the edges of the strap coils, a multiplicity of insulating blocks or buttons inserted between coil turns to maintain proper separation of the turns, an insulating support block disposed between the frame of the machine and the coil, and stainless steel, coil locating and retaining plates secured in notches provided in the inner face of the pole piece.

With this type of insulating and support structure, numerous disadvantages accrue in regard to commutating performance and assembly and repair technique. Such structures, for example, have relatively short creepage distances which have resulted in low insulation resistance problems while the notches and coil retaining plates in the face of the pole have produced an uneven pole face and thus an uneven air gap with the rotating armature.

The large number of components and the insulating block used in present insulating structures make the assembly and repair processes particularly laborious. For example, the insulating block fixes the position of the coil on the pole piece; if the block is uneven or improperly located the coil position is directly affected. Similarly, when changing the size of the air gap, the support block must be relocated and refitted accordingly since the block depends from shims or liners employed to change the air gap, the shims being disposed between the frame and the end of the pole piece.

BRIEF SUMMARY OF THE INVENTION The present invention describes an insulating support structure for commutating coils which eliminates the problems outlined above. The present disclosure accomplishes this with the use of rigid, comb-like insulating structures secured to the sides of the pole piece body with the coil turns held in place between teeth or lateral projections of the comb-like structures.

With such a structure, the creepage distance between coil turns and between the pole body is maintained by the rigid insulating structures and the teeth thereof; the numerous small insulating blocks between the turns and the large support block between the frame and coil are thereby eliminated. The commutating c011 and pole can now be assembled and disassembled and the air gaps changed without regard for said blocks (and the laborious fitting processes attendant therewith) since the coil is now secured to the pole as an insulated unit.

Similarly, the coil locating and retaining plates, and accommodating notches in the pole face, are rendered unnecessary; the rigid insulating structures of the present invention locate and retain the coil on the pole body without need of further means or assembly processes; the pole face in the present disclosure is left smooth thereby effecting an even commutating air gap with the armature.

Thus, the insulation structure of the present disclosure provides a commutating pole assembly having both improved electrical and mechanical qualities.

THE DRAWING The invention, and the objects and advantages thereof will be more apparent from reading the following detailed description in connection with the accompanying drawing in which:

The sole figure shows a perspective view of an insulating support structure and a commutating field winding constructed in accordance with the principles of the invention, with parts in section.

PREFERRED EMBODIMENTS In the figure of the drawing there is shown a perspective view of the invention in which a commutating pole assembly 10 includes an edge wound coil 12 (shown in broken-away turn portions 13) disposed on an elongated pole body 14 having a substantially rectangular cross-section. The pole body is suitably attached to the frame 16 (only partially shown) of a dynamoelectric machine.

Commutating poles, as well known in the art, are secured to the inner surface of a machine frame at intermediate or interpole locations between main poles (-not shown), and extend radially inwardly from the frame towards a rotatable armature. In the figure, the pole body 14 thus has a radial outer face or end portion 15 secured to the inner surface 16 of the frame 16, and a radial inner face portion 17 disposed adjacent a rotatable armature 1 8 (only representatively shown) to form an air gap 19 therewith.

More specifically, the invention includes an insulating structure for supporting the coil 12 as a unit on the pole body 14. The insulating structure comprises essentially two rigid insulating spacers 20 and 21 attached to the two narrow ends or sides 22 and 23 of the pole body, and two rigid elongated insulating spacers 24 and 25 attached to the Wide or elongated sides 26 and 27 of the pole body about midway therealong, the spacers 20 and 24 being in clear view in the figure.

As seen from the figure, the spacers 20 and 21 are essentially fiat, rectangular shaped pieces having slots and teeth 28 and 29 respectively provided in two opposed edges thereof. Thus, the edges of the spacers 20 and 21 take on a comb-like configuration with the main body portions thereof secured flatly against the two narrow ends 22 and 23 of the pole body.

The plane of the spacers 20 and 21, with their teeth 29, extend in the plane of the narrow sides or ends 22 and 23, the teeth 29 and slots 28 thereof extending beyond and perpendicular to the planes of the two wide or elongated sides 26 and 27 of the pole body.

The configuration of the elongated spacers 24 and 25 is somewhat different from that of the spacers 20 and 21 because of their different locations on the pole body 14. The spacers 24 and 25- are essentially elongated structures having a rectangular cross-section, and transverse slots 30 are formed in the structure along the length thereof. The slots 30 form cube-like teeth 32. The elongated spacers 24 and 25 are attached to the wide sides 26 and 27 of the pole body in such a manner that the slots and cube-like teeth extend outwardly from the wide sides in a direction essentially perpendicular thereto. In this manner, the slots and the teeth of all four of the insulating spacers 20, 21, 24 and 25 extend or protrude in the same outward direction, namely in an outward direction perpendicular to the plane of the elongated sides 26 and 27 of the pole body 14. In like manner, all of their slots and teeth lie in a plane outwardly removed from the plane of the wide sides 26 and 27.

The insulating spacers 20, 21, 24 and 25 are further positioned on the pole body 14 in a manner to place the slots 28 and 30, and the teeth 29 and 32, respectively, in substantial alignment along the depth dimension of the pole so that the turns 13 of the coil 12 can seat in the slots, and the teeth of the spacers can extend between the turns 13 as shown. In this manner the coil 12 is held firmly as a unit on the pole body 14 without further supporting and insulating structure. The teeth 29 and 32 of the insulating spacers maintain proper separation of the turns 13 without the use of individually inserted insulating blocks or buttons of the prior art, while the main body portions of the spacers separate the entire coil 12 from the pole body. The insulating spacers are securely attached to the pole body, for example with attaching hardware 35 and 36 as shown in the figure or by other suitable means.

Between the inner radial surface 16' of the frame 16 and the outer radial face or end portion 15 of the pole body 14 is disposed at shim or liner 40. Such a liner or liners are employed to change the air gap 19 between the inner radial face portion 17 of the pole body 12 and the armature 18. As can be readily appreciated, a liner 40 can be added or removed, and the air gap thereby changed without having to remove and relocate a support block and the coil 12 since the coil is now supported as a unit on the pole body thereby eliminating the need of the support block.

Before the pole assembly is assembled, an insulating layer 42 may be disposed around the pole body 14 to further insulate the pole from the turns 13 of the coil 12. The layer 42, if used, can be formed by coating the pole body with resinous material, or the layer may comprise an insulating cell or jacket preformed to fit the pole body.

As is further evident from the insulating support structure shown in the figure and described above, no other coil locating and retaining means are necessary as was the case with prior art structures. Thus, the inner face 17 of the pole body 14 of the present disclosure is permitted to remain smooth and free of coil locating and retaining plates and plate accommodating notches; the coil 12 needs no other retaining or locating means than that pro vided by the insulating spacers 20, 21, 24 and 25. For this reason, the commutating air gap 19 is smooth along the length of the pole thereby improving the quality of commutation.

From the foregoing description it should be now apparent that a new and useful coil insulating and support structure has been disclosed which eliminates the problems of presently used structures in an economical manner and with a minimum of components. With the insulating spacers of the invention secured to the'pole body 14, proper creepage distances are maintained and the coil 12 firmly supported as a unit without the need of further insulating and support components.

Though the invention has been described with a certain degree of particularity, changes may be made therein without departing from the spirit and scope thereof. For example, the number (four), and the locations of the insulating spacers 20, 21, 24 and 25 may be other than that shown in the drawing and described above.

What is claimed is:

1. A pole assembly for use in a dynamoelectric machine, said assembly comprising:

a pole body having side portions and a depth dimensron,

a strap coil having a predetermined number of turns spaced along a substantial portion of the depth dimension of said pole body,

rigid insulating spacers attached to the sides of said pole body,

each of said insulating spacers having a substantially flat main body portion disposed between the sides of the pole body and the coil turns and integral lateral projections extending from said main body portions,

said rigid insulating spacers supporting said strap coil as a unit on said pole body.

2. The assembly recited in claim 1 in which the pole body is coated with a resinous insulating material.

3. The assembly recited in claim 1 in which the pole body has wide and narrow side portions, and

the insulating spacers include at least one'insulating spacer disposed against each of the wide and narrow side portions.

4. The structure recited in claim 1 in which the pole assembly is a commutating pole in the dynamoelectric machine.

5. A rigid insulating structure for supportingthe turns of a coil on a pole body having wide and narrow side portions, said structure comprising:

at least one rigid, insulating spacer attached to each of said side portions,

the insulating spacers attached to said narrow side portions having a substantially flat body portion with teeth and slots formed along at least two opposed edges thereof, said flat body portion and teeth extending in the plane of said narrow side portions, and perpendicular to the plane of the wide side portions,

the insulating spacers attached to said wide side portions having an elongated body portion with teeth and slots formed along the substantial length thereof, said teeth extending in a plane substantially perpendicular to that of said wide side portions and outwardly therefrom,

the turns of the coil being disposed in the slots of said spacers, and the teeth thereof extending between the turns.

6. The structure recited in claim 5 in which the turns of the coil are made of conductive strap material, and are mounted edgewise in the slots of the insulating spacers.

References Cited UNITED STATES PATENTS 1,162,482 11/1915 Hiss BIO-194- 1,820,398 8/1931 Sauter 310-218 1,821,796 9/1931 Glidden 3lO--194 3,333,131 7/1967 Bush 3l0-218 FOREIGN PATENTS 216,281 5/1924 Great Britain.

MILTON o. HIRSHFIELD, Primary Examiner R. SKUDY, Assistant Examiner US. Cl. X.R. 310-260 

